listchannels: add `htlc_minimum_msat` and `htlc_maximum_msat` fields.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

CHANGELOG.md

@@ -13,7 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - JSON API: `listpeers` status now shows how many confirmations until channel is open (#2405)
 - Config: Adds parameter `min-capacity-sat` to reject tiny channels.
 - JSON API: `listforwards` now includes the time an HTLC was received and when it was resolved. Both are expressed as UNIX timestamps to facilitate parsing (Issue [#2491](https://github.com/ElementsProject/lightning/issues/2491), PR [#2528](https://github.com/ElementsProject/lightning/pull/2528))
-+- JSON API: new plugin hooks `invoice_payment` for intercepting invoices before they're paid, `openchannel` for intercepting channel opens, and `htlc_accepted` to decide whether to resolve, reject or continue an incoming or forwarded payment..
+- JSON API: new plugin hooks `invoice_payment` for intercepting invoices before they're paid, `openchannel` for intercepting channel opens, and `htlc_accepted` to decide whether to resolve, reject or continue an incoming or forwarded payment..
 - plugin: the `connected` hook can now send an `error_message` to the rejected peer.
 - Protocol: we now enforce `option_upfront_shutdown_script` if a peer negotiates it.
 - JSON API: `listforwards` now includes the local_failed forwards with failcode (Issue [#2435](https://github.com/ElementsProject/lightning/issues/2435), PR [#2524](https://github.com/ElementsProject/lightning/pull/2524))
@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 (Issue [#2409](https://github.com/ElementsProject/lightning/issues/2409))
 - JSON API: new withdraw methods `txprepare`, `txsend` and `txdiscard`.
 - plugin: the `warning` notification can now detect any `LOG_UNUSUAL`/`LOG_BROKEN` level event.
+- JSON API: `listchannels` has new fields `htlc_minimum_msat` and `htlc_maximum_msat`.
 
 ### Changed
 

doc/lightning-listchannels.7

@@ -2,12 +2,12 @@
 .\"     Title: lightning-listchannels
 .\"    Author: [see the "AUTHOR" section]
 .\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
-.\"      Date: 02/18/2019
+.\"      Date: 05/31/2019
 .\"    Manual: \ \&
 .\"    Source: \ \&
 .\"  Language: English
 .\"
-.TH "LIGHTNING\-LISTCHANN" "7" "02/18/2019" "\ \&" "\ \&"
+.TH "LIGHTNING\-LISTCHANN" "7" "05/31/2019" "\ \&" "\ \&"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -206,6 +206,30 @@ message (BOLT #7)\&.
 : The number of blocks delay required to wait for on\-chain settlement when unilaterally closing the channel (BOLT #2)\&.
 .RE
 .sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+\fIhtlc_minimum_msat\fR
+: The minimum payment which can be send through this channel\&.
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+\fIhtlc_maximum_msat\fR
+: The maximum payment which can be send through this channel\&.
+.RE
+.sp
 If \fIshort_channel_id\fR or \fIsource\fR is supplied and no matching channels are found, a "channels" object with an empty list is returned\&.
 .SH "ERRORS"
 .sp

doc/lightning-listchannels.7.txt

@@ -59,6 +59,8 @@ HTLC (BOLT #2).
 transferred satoshi (BOLT #2).
 - 'delay' : The number of blocks delay required to wait for on-chain settlement
 when unilaterally closing the channel (BOLT #2).
+- 'htlc_minimum_msat' : The minimum payment which can be send through this channel.
+- 'htlc_maximum_msat' : The maximum payment which can be send through this channel.
 
 If 'short_channel_id' or 'source' is supplied and no matching channels
 are found, a "channels" object with an empty list is returned.

gossipd/gossipd.c

@@ -1948,6 +1948,8 @@ static struct gossip_halfchannel_entry *hc_entry(const tal_t *ctx,
 	e->base_fee_msat = c->base_fee;
 	e->fee_per_millionth = c->proportional_fee;
 	e->delay = c->delay;
+	e->min = c->htlc_minimum;
+	e->max = c->htlc_maximum;
 
 	return e;
 }

lightningd/gossip_control.c

@@ -389,6 +389,8 @@ static void json_add_halfchan(struct json_stream *response,
 	json_add_num(response, "base_fee_millisatoshi", he->base_fee_msat);
 	json_add_num(response, "fee_per_millionth", he->fee_per_millionth);
 	json_add_num(response, "delay", he->delay);
+	json_add_amount_msat_only(response, "htlc_minimum_msat", he->min);
+	json_add_amount_msat_only(response, "htlc_maximum_msat", he->max);
 	json_object_end(response);
 }
 

lightningd/gossip_msg.c

@@ -105,6 +105,8 @@ static void fromwire_gossip_halfchannel_entry(const u8 **pptr, size_t *max,
 	entry->delay = fromwire_u32(pptr, max);
 	entry->base_fee_msat = fromwire_u32(pptr, max);
 	entry->fee_per_millionth = fromwire_u32(pptr, max);
+	entry->min = fromwire_amount_msat(pptr, max);
+	entry->max = fromwire_amount_msat(pptr, max);
 }
 
 struct gossip_getchannels_entry *
@@ -144,6 +146,8 @@ static void towire_gossip_halfchannel_entry(u8 **pptr,
 	towire_u32(pptr, entry->delay);
 	towire_u32(pptr, entry->base_fee_msat);
 	towire_u32(pptr, entry->fee_per_millionth);
+	towire_amount_msat(pptr, entry->min);
+	towire_amount_msat(pptr, entry->max);
 }
 
 void towire_gossip_getchannels_entry(u8 **pptr,

lightningd/gossip_msg.h

@@ -27,6 +27,7 @@ struct gossip_halfchannel_entry {
 	u32 delay;
 	u32 base_fee_msat;
 	u32 fee_per_millionth;
+	struct amount_msat min, max;
 };
 
 struct gossip_getchannels_entry {